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Action needed now to halt decline of southern lakes


Friday 24 February 2017 12:28pm

Wanaka image

New Zealand risks losing its unique alpine lakes unless it stops making the same mistakes as North America and Europe, University of Otago expert Dr Marc Schallenberg says.

Two public meetings are being held in Wanaka this evening to discuss the water quality of Lakes Wanaka, Hawea and Wakatipu, and what can be done about algal blooms known as “lake snow” or “lake snot”.

“Large lakes in many parts of the world have become severely degraded from pollution and invasive species,” Dr Schallenberg says, “showing their large size and volume does not make them resilient to degradation. In fact, they appear to be quite vulnerable.”

He will address the Wanaka branch of the Royal Society at 7.30pm, as will other water scientists from around the country, council representatives and specialists from the Department of Conservation, the Ministry for the Environment and the Otago Fish and Game Council.

A freshwater expert in the Department of Zoology, Dr Schallenberg says a “chronic lack of investment” in research and monitoring of the southern lakes had made them a “management blindspot”.

“The southern great lakes and their catchments include some of New Zealand’s most cherished and iconic environments and ecosystems, attracting increasing numbers of New Zealanders and overseas tourists.

“Numerous pressures on these lakes include urban development, agricultural intensification, climate change and the arrival of invasive aquatic species. Because of a lack of knowledge, regional water plans are arguably doing the minimum required to safeguard the lakes.”

The many questions that have arisen concerning the occurrence and subsequent spread of lake snot in the Southern Great Lakes show how little is known about how our lakes respond to environmental pressures and about what the implications are for water quality and lake users, he says.

“A concerted research effort is needed to understand how vulnerable our precious large lakes are. Otherwise, we risk making the same mistakes made in North America and Europe in allowing large lakes to degrade.

“This would have serious consequences on New Zealand’s reputation as a relatively unspoilt country, upon which our tourism industry and many of our food export industries rely.”

Dr Schallenberg suggests several solutions:

  • Use of lake-monitoring buoys by regional councils to continuously monitor lake health;
  • The establishment of an Alpine Lakes Research and Education Centre in Wanaka, supported by agencies and the community;
  • Supporting a five-year Southern Great Lakes research programme application to the Ministry of Business Innovation and Employment to study how best to manage the lakes; and
  • Further community involvement to help develop more comprehensive lake and catchment management plans.

For more information, please contact:

Dr Marc Schallenberg
Research Fellow in Freshwater Science
Department of Zoology
University of Otago
Tel 03 479 8403

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